Couples who may be heading for a nasty break-up should be careful about texting because it could end up as evidence against them in divorce court.

More than 90 per cent of America's top divorce attorneys said they have seen a spike in the number of cases using evidence from iPhones and other smartphones in the past three years, according to the American Academy of Matrimonial Lawyers (AAML).

The rise in texting evidence follows a similar trend two years ago when the AAML, a professional group of 1,600 members who handle prenuptial agreements, legal separations, annulments, custody battles, property divisions and the rights of unmarried couples, noticed a surge in evidence from Facebook pages.

'With emails you can think about and rewrite them. There is a window of opportunity to rethink what you are saying but text messaging is immediate,' said Ken Altshuler, the president of the AAML. 'We get a lot of text messages that people send out without thinking.'

He described texts as 'spontaneous venting' that can come back to haunt people because they are written records of someone's thoughts, actions and intentions.

Even a text message on a phone overlooked by someone over their shoulder, if the person is credible, can cause problems in divorce hearings.

'I have used text messaging for cross examination,' said Altshuler, who has also submitted texts as evidence. 'I would say in the last six months there have been a lot of text messages involved in litigation. For whatever reason, people are texting more and not thinking about what they are texting.'

Text messaging was the most common form of divorce evidence taken from smartphones, according to the AAML poll, followed by emails, phone numbers, call histories, GPS and Internet search histories.

Altshuler believes at least part of the reason for the surge in text evidence is because people think text messaging is safe, because it isn't easy to print out.

'Not everybody can print out a text message. You have to know how to do it,' he explained.

Altshuler advises his clients not to use Facebook, which was the main source of divorce evidence from social media in a previous poll, but added that only about half follow his advice.

He is equally cautious about other emailing.

'Anything that is in writing, you have to assume that someday a judge is going to see it. So, if it is not something that you don't want a judge to see, don't write it down.'

He added it applies particularly to text messages.

'You can erase yours but it doesn't mean they erase theirs.' - Reuters